Radio communication device and response signal spreading method

ABSTRACT

A radio communication device capable of randomizing both inter-cell interference and intra-cell interference. In this device, a spreading section primarily spreads a response signal in a ZAC sequence set by a control unit. A spreading section secondarily spreads the primarily spread response signal in a block-wise spreading code sequence set by the control unit. The control unit controls the cyclic shift amount of the ZAC sequence used for the primary spreading in the spreading section and the block-wise spreading code sequence used for the secondary spreading in the spreading section according to a set hopping pattern. The hopping pattern set by the control unit is made up of two hierarchies. An LB-based hopping pattern different for each cell is defined in the first hierarchy in order to randomize the inter-cell interference. A hopping pattern different for each mobile station is defined in the second hierarchy to randomize the intra-cell interference.

TECHNICAL FIELD

The present invention relates to a radio communication apparatus andresponse signal spreading method.

BACKGROUND ART

In mobile communication, ARQ (Automatic Repeat reQuest) is applied todownlink data from a radio communication base station apparatus(hereinafter abbreviated to a “base station”) to radio communicationmobile station apparatuses (hereinafter abbreviated to “mobilestations”). That is, mobile stations feed back response signalsrepresenting error detection results of downlink data, to the basestation. Mobile stations perform a CRC (Cyclic Redundancy Check) ofdownlink data, and, if CRC=OK (no error), feed back an ACK(ACKnowledgement), and, if CRC=NG (error present), feed back a NACK(Negative ACKnowledgement), as a response signal to the base station.These response signals are transmitted to the base station using uplinkcontrol channels such as PUCCH's (Physical Uplink Control CHannels).

Also, the base station transmits control information for carryingresource allocation results of downlink data, to the mobile stations.This control information is transmitted to the mobile stations usingdownlink control channels such as L1/L2 CCH's (L1/L2 Control CHannels).Each L1/L2 CCH occupies one or a plurality of CCE's (Control ChannelElement), depending on the coding rate of control information. Forexample, when an L1/L2 CCH for carrying control information of a codingrate of ⅔ occupies one CCE, an L1/L2 CCH for carrying controlinformation of a coding rate of ⅓ occupies two CCE's, an L1/L2 CCH forcarrying control information of a coding rate of ⅙ occupies four CCE's,and an L1/L2 CCH for carrying control information of a coding rate of1/12 occupies eight CCE's. If one L1/L2 CCH occupies a plurality ofCCE's, the plurality of CCE's occupied by the L1/L2 CCH are consecutive.The base station generates an L1/L2 CCH per mobile station, allocates aCCE that should be occupied by the L1/L2 CCH depending on the number ofCCE's required by control information, maps the control information onphysical resources associated with the allocated CCE's and transmits theresults.

Also, to use downlink communication resources efficiently withoutsignaling to carry PUCCH's from the base station to the mobile stationsfor transmitting response signals, studies are underway to associateCCE's and PUCCH's on a one-to-one basis (see Non-Patent Document 1).According to this association, each mobile station can decide the PUCCHto use to transmit a response signal from that mobile station, from theCCE associated with a physical resource on which control information forthat mobile station is mapped. Therefore, each mobile station maps aresponse signal from that mobile station on a physical resource, basedon the CCE associated with the physical resource on which controlinformation for that mobile station is mapped. For example, when a CCEassociated with a physical resource on which control information for amobile station is mapped is CCE #0, the mobile station decides thatPUCCH #0 associated with CCE #0 is the PUCCH for that mobile station.Also, for example, when CCE's associated with physical resources onwhich control information for that mobile station is mapped are CCE #0to CCE #3, the mobile station decides that PUCCH #0 associated with CCE#0 of the minimum number among CCE #0 to CCE #3 is the PUCCH for thatmobile station, or, when CCE's associated with physical resources onwhich control information for that mobile station is mapped are CCE #4to CCE #7, the mobile station decides that PUCCH #4 associated with CCE#4 of the minimum number among CCE #4 to CCE #7 is the PUCCH for thatmobile station.

Also, as shown in FIG. 1, studies are underway to performcode-multiplexing by spreading a plurality of response signals from aplurality of mobile stations using ZAC (Zero Auto Correlation) sequencesand Walsh sequences (see Non-Patent Document 2). In FIG. 1, (W₀, W₁, W₂,W₃) represent Walsh sequences having a sequence length of 4. As shown inFIG. 1, in a mobile station, first, an ACK or NACK response signal issubject to the first spreading in the frequency domain by a sequencehaving a characteristic of a ZAC sequence (having a sequence length of12) in the time domain. Next, the response signal subjected to the firstspreading is subject to an IFFT (Inverse Fast Fourier Transform) inassociation with W₀ to W₃. The response signal spread in the frequencydomain is transformed to a ZAC sequence having a sequence length of 12in the time domain by this IFFT. Further, the signal subjected to theIFFT is subject to second spreading using Walsh sequences (having asequence length of 4). That is, one response signal is allocated to eachof four SC-FDMA (Single Carrier-Frequency Division Multiple Access)symbols S₀ to S₃. Similarly, response signals of other mobile stationsare spread using ZAC sequences and Walsh sequences. Here, differentmobile stations use ZAC sequences of different cyclic shift values inthe time domain or different Walsh sequences. In this case, the sequencelength of a ZAC sequence in the time domain is 12, so that it ispossible to use twelve ZAC sequences of cyclic shift values “0” to “11,”generated from the same ZAC sequence. Also, the sequence length of aWalsh sequence is 4, so that it is possible to use four different Walshsequences. Therefore, in an ideal communication environment, it ispossible to code-multiplex maximum 48 (12×4) response signals frommobile stations.

Also, as shown in FIG. 1, studies are underway to code-multiplex aplurality of reference signals (e.g., pilot signals) from a plurality ofmobile stations (see Non-Patent Document 2). As shown in FIG. 1, whenthree reference signal symbols R₀, R₁ and R₂, are generated from a ZACsequence (having a sequence length of 12), first, the ZAC sequence issubjected to an IFFT in association with orthogonal sequences [F₀, F₁,F₂] having a sequence length of 3 such as a Fourier sequence. By thisIFFT, a ZAC sequence having a sequence length of 12 in the time domainis provided. Further, the signal subjected to the IFFT is spread usingthe orthogonal sequences [F₀, F₁, F₂]. That is, one reference signal(i.e. ZAC sequence) is allocated to each of three symbols R₀, R₁ and R₂.Similarly, other mobile stations allocate one reference signal (i.e.,ZAC sequence) to each of three symbols R₀, R₁ and R₂. Here, differentmobile stations use ZAC sequences of different cyclic shift values inthe time domain or different orthogonal sequences. In this case, thesequence length of a ZAC sequence in the time domain is 12, so that itis possible to use 12 ZAC sequences of cyclic shift values “0” to “11”generated from the same ZAC sequence. Also, the sequence length of anorthogonal sequence is 3, so that it is possible to use three differentorthogonal sequences. Therefore, in an ideal communication environment,it is possible to code-multiplex maximum 36 (12×3) response signals frommobile stations.

As a result, as shown in FIG. 1, seven symbols of S₀, S₁, R₀, R₁, R₂,S₂, S₃ form one slot.

Here, cross-correlation between ZAC sequences of different cyclic shiftvalues generated from the same ZAC sequence, is virtually zero.Therefore, in an ideal communication environment, a plurality ofresponse signals subjected to spreading and code-multiplexing by ZACsequences of different cyclic shift values (0 to 11), can be separatedin the time domain by correlation processing in the base station,virtually without inter-code interference.

However, due to the influence of, for example, transmission timingdifference in mobile stations and multipath delayed waves, a pluralityof response signals from a plurality of mobile stations do not alwaysarrive at a base station at the same time. For example, if thetransmission timing of a response signal spread by a ZAC sequence of thecyclic shift value “0” is delayed from the correct transmission timing,the correlation peak of the ZAC sequence of the cyclic shift value “0”may appear in the detection window for the ZAC sequence of the cyclicshift value “1.” Further, if a response signal spread by the ZACsequence of the cyclic shift value “0” has a delayed wave, interferenceleakage due to the delayed wave may appear in the detection window forthe ZAC sequence of the cyclic shift value “1.” That is, in these cases,the ZAC sequence of the cyclic shift value “1” is interfered by the ZACsequence of the cyclic shift value “0.” Therefore, in these cases, theseparation performance degrades between a response signal spread by theZAC sequence of the cyclic shift value “0” and a response signal spreadby the ZAC sequence of the cyclic shift value “1.” That is, if ZACsequences of adjacent cyclic shift values are used, the separationperformance of response signals may degrade.

Therefore, up till now, if a plurality of response signals arecode-multiplexed by spreading using ZAC sequences, a cyclic shiftinterval (i.e., a difference of cyclic shift values) is provided betweenthe ZAC sequences such that inter-code interference does not occurbetween the ZAC sequences. For example, when the cyclic shift intervalbetween ZAC sequences is 2, only six ZAC sequences of cyclic shiftvalues “0,” “2,” “4,” “6,” “8” and “10” are used in the first spreadingof response signals, among twelve ZAC sequences of cyclic shift values“0” to “11” having a sequence length of 12. Therefore, if Walshsequences having a sequence length of 4 are used in second spreading ofresponse signals, it is possible to code-multiplex maximum 24 (6×4)response signals from mobile stations.

However, as shown in FIG. 1, the sequence length of orthogonal sequencesused to spread reference signals is 3, and therefore only threedifferent orthogonal sequences can be used to spread reference signals.Therefore, when a plurality of response signals are separated using thereference signals shown in FIG. 1, only maximum 18 (6×3) responsesignals from mobile stations can be code-multiplexed. Therefore, threeWalsh sequences among four Walsh sequences having a sequence length of 4are enough, and therefore one Walsh sequence is not used.

Also, one SC-FDMA symbol shown in FIG. 1 may be referred to as one “LB(Long Block).” Therefore, a spreading code sequence used for spreadingin symbol units (i.e., in LB units) is referred to as a “block-wisespreading code sequence.”

Also, studies are underway to define 18 PUCCH's shown in FIG. 2.Normally, between mobile stations using different block-wise spreadingcode sequences, the orthogonality of response signals do not collapseunless those mobile stations move fast. However, between mobile stationsusing the same block-wise spreading code sequence, especially when thereis a large difference of received power between response signals fromthose mobile stations in a base station, one response signal may beinterfered with from another response signal. For example, in FIG. 2, aresponse signal using PUCCH #3 (cyclic shift value=2) may be interferedwith from a response signal using PUCCH #0 (cyclic shift value=0).

To reduce such interference, a technique of cyclic shift hopping isstudied (see Non-Patent Document 3). Cyclic shift hopping is thetechnique of changing the cyclic shift values to allocate to the symbolsin FIG. 1, over time, in a random manner. By this means, it is possibleto randomize the combinations of response signals to cause interference,and prevent only part of mobile stations from having strong interferencecontinuously. That is, by cyclic shift hopping, it is possible torandomize interference.

Here, interference between response signals can be classified broadlyinto inter-cell interference which refers to the interference causedbetween cells and intra-cell interference which refers to theinterference caused between mobile stations in one cell. Therefore,interference randomization is classified broadly into inter-cellinterference randomization and intra-cell interference randomization.

-   Non-Patent Document 1: Implicit Resource Allocation of ACK/NACK    Signal in E-UTRA Uplink    (ftp://ftp.3gpp.org/TSG_RAN/WG1_RL1/TSGR1_(—)49/Docs/R1-072439.zip)-   Non-Patent Document 2: Multiplexing capability of CQIs and ACK/NACKs    form different UEs    (ftp://ftp.3gpp.org/TSG_RAN/WG1_RL1/TSGR1_(—)49/Docs/R1-072315.zip)-   Non-Patent Document 3: Randomization of intra-cell interference in    PUCCH    (ftp://ftp.3gpp.org/TSG_RAN/WG1_RL1/TSGR1_(—)50/Docs/R1-073412.zip)

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

Here, in inter-cell interference, a response signal of a mobile stationin one cell is interfered with from a plurality of response signalsusing the same cyclic shift value as that of the response signal of thatstation in another cell, and, consequently, many cyclic shift hoppingpatterns (hereinafter abbreviated to “hopping patterns”) are required torandomize inter-cell interference sufficiently. Therefore, to randomizeinter-cell interference sufficiently, it is necessary to perform cyclicshift hopping that changes the cyclic shift value per LB (i.e., perSC-FDMA symbol), that is, it is necessary to perform LB-based cyclicshift hopping (i.e., SC-FDMA symbol-based cyclic shift hopping).

On the other hand, to randomize intra-cell interference, allocation ofrespective hopping patterns to response signals of all mobile stationsin one cell is possible. However, there arises a problem that, with anincrease of hopping patterns, the overhead of control signals forcarrying hopping patterns between a base station and mobile stationsincreases. Also, there arises a problem that, when a plurality of mobilestations in the same cell perform LB-based cyclic shift hopping uniqueto individual mobile stations, the relative relationships between thecyclic shift values of S₀, 5 ₁, S₂ and S₃ or R₀, R₁ and R₂ multiplied byblock-wise spreading code sequences in the mobile stations, maycollapse, and therefore the orthogonality between mobile stations usingdifferent block-wise spreading code sequences may collapse. For example,in FIG. 2, although PUCCH #3 should be normally interfered with onlyfrom PUCCH #0, due to the collapse of the orthogonality betweenblock-wise spreading code sequences, PUCCH #3 is interfered with notonly from PUCCH #0 but also from PUCCH #1 and PUCCH #2.

The above problem can be solved by performing slot-based cyclic shifthopping instead of LB-based cyclic shift hopping, that is, by changingthe cyclic shift value on a per slot basis.

However, by performing slot-based cyclic shift hopping instead ofLB-based cyclic shift hopping, there arises a new problem thatinter-cell interference cannot be randomized sufficiently.

That is, there is a contradiction between a hopping pattern suitable forinter-cell interference randomization and a hopping pattern suitable forintra-cell interference randomization.

It is therefore an object of the present invention to provide a radiocommunication apparatus and response signal spreading method forrandomizing both inter-cell interference and intra-cell interference.

Means for Solving the Problem

The radio communication apparatus of the present invention employs aconfiguration having: a first spreading section that performs firstspreading of a response signal using one of a plurality of firstsequences that can be separated from each other because of differentcyclic shift values; and a control section that controls the firstsequence used in the first spreading section, according to hoppingpatterns for a plurality of control channels associated with theplurality of first sequences, where the hopping patterns comprise asymbol-based first layer hopping pattern that varies between cells, anda slot-based second layer hopping pattern that varies between radiocommunication apparatuses.

The response signal spreading method of the present invention includes:a first spreading step of performing first spreading of a responsesignal using one of a plurality of first sequences that can be separatedfrom each other because of different cyclic shift values; and a controlstep of controlling the first sequence used in the first spreading step,according to hopping patterns for a plurality of control channelsassociated with the plurality of first sequences, where the hoppingpatterns comprise a symbol-based first layer hopping pattern that variesbetween cells, and a slot-based second layer hopping pattern that variesbetween radio communication apparatuses.

Advantageous Effect of the Invention

According to the present invention, it is possible to randomize bothinter-cell interference and intra-cell interference.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a method for spreading a response signal and referencesignal (prior art);

FIG. 2 shows the definition of PUCCH's (prior art);

FIG. 3 is a block diagram showing the configuration of a base stationaccording to Embodiment 1 of the present invention;

FIG. 4 is a block diagram showing the configuration of a mobile stationaccording to Embodiment 1 of the present invention;

FIG. 5A shows a hopping pattern according to Embodiment 1 of the presentinvention (slot 0 in cell 0 in example 1-1);

FIG. 5B shows a hopping pattern according to Embodiment 1 of the presentinvention (slot 1 in cell 0 in example 1-1);

FIG. 6A shows a hopping pattern according to Embodiment 1 of the presentinvention (slot 0 in cell 1 in example 1-1);

FIG. 6B shows a hopping pattern according to Embodiment 1 of the presentinvention (slot 1 in cell 1 in example 1-1);

FIG. 7A shows a second layer hopping pattern according to Embodiment 1of the present invention (slot 0 in example 1-1);

FIG. 7B shows a second layer hopping pattern according to Embodiment 1of the present invention (slot 1 in example 1-1);

FIG. 8A shows a second layer hopping pattern according to Embodiment 1of the present invention (slot 0 in example 1-2);

FIG. 8B shows a second layer hopping pattern according to Embodiment 1of the present invention (slot 1 in example 1-2);

FIG. 8C shows a second layer hopping pattern according to Embodiment 1of the present invention (slot 1 in example 1-3);

FIG. 9A shows a second layer hopping pattern according to Embodiment 1of the present invention (slot 0 in example 1-4);

FIG. 9B shows a second layer hopping pattern according to Embodiment 1of the present invention (slot 1 in example 1-4);

FIG. 10A shows a second layer hopping pattern according to Embodiment 2of the present invention (slot 0);

FIG. 10B shows a second layer hopping pattern according to Embodiment 2of the present invention (slot 1);

FIG. 11A shows a second layer hopping pattern according to Embodiment 2of the present invention (slot 0); and

FIG. 11B shows a second layer hopping pattern according to Embodiment 2of the present invention (slot 1);

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be explained below in detailwith reference to the accompanying drawings.

Embodiment 1

FIG. 3 shows the configuration of base station 100 according to thepresent embodiment, and FIG. 4 shows the configuration of mobile station200 according to the present embodiment.

Here, to avoid complicated explanation, FIG. 3 shows componentsassociated with transmission of downlink data and components associatedwith reception of uplink response signals to downlink data, which areclosely related to the present invention, and the illustration andexplanation of the components associated with reception of uplink datawill be omitted. Similarly, FIG. 4 shows components associated withreception of downlink data and components associated with transmissionof uplink response signals to downlink data, which are closely relatedto the present invention, and the illustration and explanation of thecomponents associated with transmission of uplink data will be omitted.

Also, in the following explanation, a case will be described where ZACsequences are used in the first spreading and block-wise spreading codesequences are used in second spreading. Here, in the first spreading, itis equally possible to use sequences that can be separated from eachother because of different cyclic shift values, other than ZACsequences. For example, in the first spreading, it is equally possibleto use GCL (Generalized Chirp Like) sequences, CAZAC (Constant AmplitudeZero Auto Correlation) sequences, ZC (Zadoff-Chu) sequences, or use PNsequences such as M sequences and orthogonal gold code sequences. Also,in second spreading, as block-wise spreading code sequences, it ispossible to use any sequences that can be regarded as orthogonalsequences or substantially orthogonal sequences. For example, in secondspreading, it is possible to use Walsh sequences or Fourier sequences asblock-wise spreading code sequences.

Also, in the following explanation, twelve ZAC sequences of cyclic shiftvalues “0” to “11” having a sequence length of 12 are expressed as ZAC#0 to ZAC #11, and three block-wise code sequences of sequence numbers“0” to “2” having a sequence length of 4 are expressed as BW #0 to BW#2. However, the present invention is not limited to these sequencelengths.

Also, in the following explanation, the PUCCH numbers are defined by thecyclic shift values of ZAC sequences and the sequence numbers ofblock-wise spreading code sequences. That is, a plurality of resourcesfor response signals are defined by ZAC #0 to ZAC #11 that can beseparated from each other because of different cyclic shift values andBW #0 to BW #2 that are orthogonal to each other.

Also, the following explanation presumes that the CCE numbers and thePUCCH numbers are associated on a one-to-one basis. That is, CCE #0 andPUCCH #0 are associated with each other, CCE #1 and PUCCH #1 areassociated with each other, CCE #2 and PUCCH #2 are associated with eachother, and so on.

In base station 100 shown in FIG. 3, control information generatingsection 101 and mapping section 104 receive as input a resourceallocation result of downlink data. Also, control information generatingsection 101 and encoding section 102 receive as input the coding rate ofcontrol information per mobile station for carrying a resourceallocation result of downlink data, as coding rate information. Here, inthe same way as above, the coding rate of control information is one of⅔, ⅓, ⅙ and 1/12.

Control information generating section 101 generates control informationper mobile station for carrying a resource allocation result, andoutputs the control information to encoding section 102. Controlinformation, which is provided per mobile station, includes mobilestation ID information to indicate to which mobile station the controlinformation is directed. For example, control information includes, asmobile station ID information, CRC bits masked by the ID number of themobile station to which that control information is carried. Further,according to the coding rate information received as input, controlinformation generating section 101 performs L1/L2 CCH allocation foreach mobile station based on the number of CCE's (i.e., the number ofCCE's occupied) required to carry control information, and outputs theCCE number associated with the allocated L1/L2 CCH to mapping section104. Here, in the same way as above, an L1/L2 CCH occupies one CCE whenthe coding rate of control information is ⅔. Therefore, an L1/L2 CCHoccupies two CCE's when the coding rate of control information is ⅓, anL1/L2 CCH occupies four CCE's when the coding rate of controlinformation is ⅙, and an L1/L2 CCH occupies eight CCE's when the codingrate of control information is 1/12. Also, in the same way as above,when one L1/L2 CCH occupies a plurality of CCE's, the plurality of CCE'soccupied are consecutive.

Encoding section 102 encodes control information on a per mobile stationbasis according to the coding rate information received as input, andoutputs the results to modulating section 103.

Modulating section 103 modulates the encoded control information andoutputs the result to mapping section 104.

On the other hand, encoding section 105 encodes and outputs transmissiondata for each mobile station (i.e., downlink data) to retransmissioncontrol section 106.

Upon the initial transmission, retransmission control section 106 holdsand outputs encoded transmission data per mobile station to modulatingsection 107. Retransmission control section 106 holds transmission datauntil an ACK from each mobile station is received as input from decidingsection 116. Also, when a NACK from each mobile station is received asinput from deciding section 116, that is, upon retransmission,retransmission control section 106 outputs transmission data associatedwith that NACK to modulating section 107.

Modulating section 107 modulates the encoded transmission data receivedas input from retransmission control section 106, and outputs the resultto mapping section 104.

Upon transmission of control information, mapping section 104 maps thecontrol information received as input from modulating section 103 on aphysical resource based on the CCE number received as input from controlinformation generating section 101, and outputs the result to IFFTsection 108. That is, mapping section 104 maps control information onthe subcarrier corresponding to the CCE number among a plurality ofsubcarriers forming an OFDM symbol, on a per mobile station basis.

On the other hand, upon transmission of downlink data, mapping section104 maps transmission data for each mobile station on a physicalresource based on a resource allocation result, and outputs the mappingresult to IFFT section 108. That is, based on a resource allocationresult, mapping section 104 maps transmission data on part of aplurality of subcarriers forming an OFDM symbol, on a per mobile stationbasis.

IFFT section 108 generates an OFDM symbol by performing an IFFT of aplurality of subcarriers on which control information or transmissiondata is mapped, and outputs the OFDM symbol to CP (Cyclic Prefix)attaching section 109.

CP attaching section 109 attaches the same signal as the signal at thetail end part of the OFDM symbol, to the head of that OFDM symbol, as aCP.

Radio transmitting section 110 performs transmission processing such asD/A conversion, amplification and up-conversion on the OFDM symbol witha CP, and transmits the result from antenna 111 to mobile station 200(in FIG. 3).

On the other hand, radio receiving section 112 receives a responsesignal or reference signal transmitted from mobile station 200, viaantenna 111, and performs receiving processing such as down-conversionand A/D conversion on the response signal or reference signal.

CP removing section 113 removes the CP attached to the response signalor reference signal subjected to receiving processing.

Despreading section 114 despreads the response signal by the block-wisespreading code sequence used in second spreading in mobile station 200,and outputs the despread response signal to correlation processingsection 115. Similarly, despreading section 114 despreads the referencesignal by the orthogonal sequence that is used to spread a referencesignal in mobile station 200, and outputs the despread response signalto correlation processing section 115.

Correlation processing section 115 finds the correlation value betweenthe despread response signal and the ZAC sequence that is used in thefirst spreading in mobile station 200, and the correlation value betweenthe despread reference signal and that ZAC sequence, and outputs thecorrelation values to deciding section 116.

Deciding section 116 detects a response signal on a per mobile stationbasis, by detecting the correlation peaks in the detection windows on aper mobile station basis. For example, upon detecting the correlationpeak in detection window #0 for mobile station #0, deciding section 116detects the response signal from mobile station #0. Further, decidingsection 116 decides whether the detected response signal is an ACK orNACK, by synchronization detection using the correlation value of thereference signal, and outputs the ACK or NACK to retransmission controlsection 106 on a per mobile station basis.

On the other hand, in mobile station 200 shown in FIG. 4, radioreceiving section 202 receives an OFDM symbol transmitted from basestation 100, via antenna 201, and performs receiving processing such asdown-conversion and A/D conversion on the OFDM symbol.

CP removing section 203 removes the CP attached to the OFDM symbolsubjected to receiving processing.

FFT (Fast Fourier Transform) section 204 acquires control information ordownlink data mapped on a plurality of subcarriers by performing an FFTof the OFDM symbol, and outputs the control information or downlink datato extracting section 205.

Extracting section 205 and decoding section 207 receive as input codingrate information indicating the coding rate of control information, thatis, information indicating the number of CCE's occupied by an L1/L2 CCH.

Upon receiving the control information, extracting section 205 extractsthe control information from the plurality of subcarriers according tothe coding rate information received as input, and outputs the controlinformation to demodulating section 206.

Demodulating section 206 demodulates and outputs the control informationto decoding section 207.

Decoding section 207 decodes the control information according to thecoding rate information received as input, and outputs the result todeciding section 208.

On the other hand, upon receiving downlink data, extracting section 205extracts the downlink data directed to the subject mobile station fromthe plurality of subcarriers, based on the resource allocation resultreceived as input from deciding section 208, and outputs the downlinkdata to demodulating section 210. This downlink data is demodulated indemodulating section 210, decoded in decoding section 211 and receivedas input in CRC section 212.

CRC section 212 performs an error detection of the decoded downlink datausing a CRC, generates an ACK in the case of CRC=OK (no error) or a NACKin the case of CRC=NG (error present), as a response signal, and outputsthe generated response signal to modulating section 213. Further, in thecase of CRC=OK (no error), CRC section 212 outputs the decoded downlinkdata as received data.

Deciding section 208 performs a blind detection of whether or not thecontrol information received as input from decoding section 207 isdirected to the subject mobile station. For example, deciding section208 decides that, if CRC=OK (no error) as a result of demasking CRC bitsby the ID number of the subject mobile station, control information isdirected to that mobile station. Further, deciding section 208 outputsthe control information directed to the subject mobile station, that is,the resource allocation result of downlink data for that mobile station,to extracting section 205.

Further, deciding section 208 decides a PUCCH that is used to transmit aresponse signal from the subject mobile station, from the CCE numberassociated with subcarriers on which the control information directed tothat mobile station is mapped, and outputs the decision result (i.e.,PUCCH number) to control section 209. For example, if a CCE associatedwith subcarriers on which control information directed to the subjectmobile station is CCE #0 as above, deciding section 208 decides thatPUCCH #0 associated with CCE #0 is the PUCCH for that mobile station.Also, for example, if CCE's associated with subcarriers on which controlinformation directed to the subject mobile station is mapped are CCE #0to CCE #3, deciding section 208 decides that PUCCH #0 associated withCCE #0 of the minimum number among CCE #0 to CCE #3 is the PUCCH forthat mobile station, and, if CCE's associated with subcarriers on whichcontrol information directed to the subject mobile station is mapped areCCE #4 to CCE #7, deciding section 208 decides that PUCCH #4 associatedwith CCE #4 of the minimum number among CCE #4 to CCE #7 is the PUCCHfor that mobile station.

Based on a set hopping pattern and the PUCCH number received as inputfrom deciding section 208, control section 209 controls the cyclic shiftvalue of the ZAC sequence used in the first spreading in spreadingsection 214 and the block-wise spreading code sequence used in secondspreading in spreading section 217. That is, according to a set hoppingpattern, control section 209 selects the ZAC sequence of the cyclicshift value associated with the PUCCH number received as input fromdeciding section 208, among ZAC #0 to ZAC #11, and sets the ZAC sequencein spreading section 214, and selects the block-wise spreading codesequence associated with the PUCCH number received as input fromdeciding section 208, among BW #0 to BW #2, and sets the block-wisespreading code sequence in spreading section 217. That is, controlsection 209 selects one of the plurality of resources defined by ZAC #0to ZAC #11 and BW #0 to BW #2. The sequence control in control section209 will be described later in detail. Also, control section 209 outputsa ZAC sequence to IFFT section 220 as a reference signal.

Modulating section 213 modulates the response signal received as inputfrom CRC section 212 and outputs the result to spreading section 214.

Spreading section 214 performs first spreading of the response signal bythe ZAC sequence set in control section 209, and outputs the responsesignal subjected to the first spreading to IFFT section 215. That is,spreading section 214 performs first spreading of the response signalusing the ZAC sequence of the cyclic shift value associated with theresource selected based on the hopping pattern in control section 209.

IFFT section 215 performs an IFFT of the response signal subjected tothe first spreading, and outputs the response signal subjected to anIFFT to CP attaching section 216.

CP attaching section 216 attaches the same signal as the tail end partof the response signal subjected to an IFFT, to the head of thatresponse signal as a CP.

Spreading section 217 performs second spreading of the response signalwith a CP by the block-wise spreading code sequence set in controlsection 209, and outputs the response signal subjected to secondspreading to multiplexing section 218. That is, spreading section 217performs second spreading of the response signal subjected to the firstspreading, using the block-wise spreading code sequence associated withthe resource selected in control section 209.

IFFT section 220 performs an IFFT of the reference signal and outputsthe reference signal subjected to an IFFT to CP attaching section 221.

CP attaching section 221 attaches the same signal as the tail end partof the reference signal subjected to an IFFT, to the head of thatreference signal as a CP.

Spreading section 222 spreads the reference signal with a CP by apredetermined orthogonal sequence and outputs the spread referencesignal to multiplexing section 218.

Multiplexing section 218 time-multiplexes the response signal subjectedto second spreading and the spread reference signal in one slot, andoutputs the result to radio transmitting section 219.

Radio transmitting section 219 performs transmission processing such asD/A conversion, amplification and up-conversion on the response signalsubjected to second spreading or the spread reference signal, andtransmits the result from antenna 201 to base station 100 (in FIG. 3).

Next, sequence control in control section 209 will be explained indetail.

Inter-cell interference randomization presumes the presence of aplurality of mobile stations that interfere with one mobile station,requiring many hopping patterns for inter-cell interferencerandomization. Therefore, LB-based cyclic shift hopping is suitable forinter-cell interference randomization.

On the other hand, there are only one or two mobile stations thatinterfere with one mobile station in intra-cell interference, and,consequently, it is sufficient to provide a small number of hoppingpatterns for intra-cell interference randomization. Also, if LB-basedcyclic shift hopping is performed for intra-cell interference, theorthogonality between block-wise spreading code sequences may collapseas above.

Therefore, the present embodiment defines and sets two-layered hoppingpatterns in control section 209. That is, in the first layer, LB-basedhopping patterns that vary between cells are defined for randomizinginter-cell interference. Here, in the first layer, all mobile stationsin the same cell use the same hopping pattern. Also, in the secondlayer, hopping patterns that vary between mobile stations in the samecell are defined for randomizing intra-cell interference. Here, not tocollapse the orthogonality between block-wise spreading code sequences,assume that the second layer hopping patterns refer to slot-basedhopping patterns. Also, to reduce the signaling amount required to carrythe hopping patterns, assume that the second layer hopping patternsrefer to the hopping patterns that are common between a plurality ofcells.

Thus, each mobile station performs hopping using hopping patternsrepresented by a first layer hopping pattern and a second layer hoppingpattern (i.e., hopping patterns 1+2). That is, hopping patterns 1+2 areset in control section 209, and control section 209 performs sequencecontrol according to the set hopping patterns 1+2.

Also, hopping patterns 1+2 may be carried from a base station to eachmobile station. Also, by associating first layer hopping patterns andcell ID's on a one-to-one basis, the signaling amount required to carryfirst layer hopping patterns may be reduced. Also, as described above, ahopping pattern that is common between a plurality of cells is used as asecond layer hopping pattern, and, consequently, by setting second layerhopping patterns uniquely according to the PUCCH numbers in slot 0, thesignaling amount required to carry second layer hopping patterns may bereduced.

Sequence control based on hopping patterns 1+2 will be explained belowin detail.

Example 1-1 FIGS. 5A, 5B, 6A, 6B, 7A and 7B

The hopping patterns 1+2 shown in FIGS. 5A and 5B are used in cell 0,and the hopping patterns 1+2 shown in FIGS. 6A and 6B are used in cell 1adjacent to cell 0.

As shown in FIG. 5A, in slot 0, all PUCCH's of PUCCH #0 to PUCCH #17keep relative relationships and change the cyclic shift values on a perLB basis, according to the same first layer hopping pattern unique tocell 0. In other words, in slot 0, LB-based hopping unique to cell 0 isperformed.

Also, as shown in FIG. 5B, in slot 1 subsequent to slot 0, as in slot 0,LB-based hopping unique to cell 0 is performed according to the firstlayer hopping pattern unique to cell 0. That is, in each slot in cell 0,LB-based hopping is performed according to the first layer hoppingpattern that is common between slots and that is unique to cell 0.However, in slot 1, PUCCH #5 is present in the position in which PUCCH#0 is essentially present, and PUCCH #0 is present in the position inwhich PUCCH #5 is essentially present. That is, in slot 1, thearrangement order of PUCCH's on the cyclic shift axis is opposite tothat in slot 0. For example, referring to BW #0 (first row), whilePUCCH's are arranged in order from PUCCH #0, PUCCH #1, PUCCH #2, PUCCH#3, PUCCH #4 to PUCCH #5 in slot 0, PUCCH's are arranged in order fromPUCCH #5, PUCCH #4, PUCCH #3, PUCCH #2, PUCCH #1 to PUCCH #0 in slot 1.Thus, in the present example, a slot-based second layer hopping patternunique to a mobile station is defined by reversing the arrangement orderof PUCCH's on the cyclic shift axis on a per slot basis.

Also, in each slot in cell 1, as shown in FIGS. 6A and 6B, LB-basedhopping is performed according to the first layer hopping pattern thatis common between slots and that is unique to cell 1 different from cell0. On the other hand, even in cell 1, as shown in FIGS. 6A and 6B, aslot-based second layer hopping pattern unique to a mobile station isdefined by reversing the arrangement order of PUCCH's on the cyclicshift axis.

Hopping in the present example is represented by equation 1. That is,the cyclic shift value CS_(index)(k,i,cell_(id)) used by the k-th PUCCHin the i-th LB (SC-FDMA symbol) in the cell of the cell index cell_(id),is given by equation 1. Here, init(k) is the cyclic shift value used bythe k-th PUCCH in LB0 (first LB). Also, Hop_(LB)(i,cell_(id)) is acell-specific, LB-based hopping pattern that is set for randomizinginter-cell interference and that is common between all mobile stationsin the same cell. Also, Hop_(slot)(k,j) is a PUCCH-specific, slot-basedhopping pattern that is set for randomizing intra-cell interference andthat is common between all cells.

CS_(index)(k,i,cell_(id))=mod(init(k)+Hop_(LB)(i,cell_(id))+Hop_(slot)(k,j),12)  (Equation1)

Here, when one slot is formed with 7 LB's, the relationship shown inFIG. 2 holds between i and j. In this case, floor(x) represents themaximum integer equal to or less than x.

j=floor(i/7)  (Equation 2)

Therefore, in FIGS. 5A and 5B, Hop_(LB)(i,cell_(id)) is defined byequation 3, and Hop_(slot)(k,j) is defined by one of equations 4, 5 and6.

Hop_(LB)(i,cell_(id))=2i  (Equation 3)

Hop_(slot)(k,j)=0 (for j=0)  (Equation 4)

Hop_(slot)(k,j)=10−init(k) (for j=1)  (Equation 5)

Hop_(slot)(k,j)=12−init(k) (for j=1)  (Equation 6)

Here, FIGS. 7A and 7B show second layer hopping patterns (i.e.,slot-based hopping patterns) common between cell 0 and cell 1. FIGS. 7Aand 7B show second layer hopping patterns extracted from FIGS. 5A, 5B,6A and 6B. From FIGS. 7A and 7B, it is understood that a second layerhopping pattern (i.e., slot-based hopping pattern) is a hopping patternthat is common between cell 0 and cell 1. Also, the arrow direction(i.e., the right direction) in FIGS. 7A and 7B indicates the directionin which interference is likely to occur. From FIGS. 7A and 7B, it isunderstood that PUCCH's that are likely to be interference sources amongall PUCCH's from PUCCH #0 to PUCCH #17 vary between slot 0 and slot 1.For example, while PUCCH #1 is subject to interference from PUCCH #0 inslot 0, PUCCH #1 is subject to interference from PUCCH #3 in slot 1.That is, according to the present example, by simple slot-based hoppingpatterns defined by reversing the arrangement order of PUCCH's on thecyclic shift axis on a per slot basis, it is possible to randomizeintra-cell interference.

Thus, according to the present example, it is possible to maintain theorthogonality between block-wise spreading code sequences, and randomizeboth inter-cell interference and intra-cell interference. Also, firstlayer hopping patterns are common between all mobile stations in thesame cell, so that it is possible to carry first layer hopping patternscollectively from a base station to all mobile stations in that cell.For example, a base station may carry first layer hopping patterns tomobile stations using BCH's (Broadcast CHannels). Also, by associatingcell ID's (i.e., cell indices) and first layer hopping patterns andcarrying the cell ID (cell index) of the subject cell to mobilestations, a base station may carry first layer hopping patterns to themobile stations. Also, according to the present example, a hoppingpattern that varies between mobile stations refers to a slot-basedhopping pattern, so that it is possible to reduce the number of hoppingpatterns and reduce the signaling amount required to carry hoppingpatterns. Also, a second layer hopping pattern refers to a hoppingpattern that is common between a plurality of cells, so that it ispossible to further reduce the signaling amount required to carry secondlayer hopping patterns.

Example 1-2 FIGS. 8A and 8B

When mobile stations move fast, interference occurs not only in thearrow direction shown in FIGS. 7A and 7B (i.e., the right direction) butalso in the arrow direction shown in FIG. 8A (i.e., verticaldirections). This is because, up to now, BW #0=(1, 1, 1, 1), BW #1=(1,−1, 1, −1), and BW #2=(1, −1, −1, 1) are defined, and therefore theorthogonality between BW #1 and BW #2 is more likely to collapse thanthe orthogonality between BW #0 and BW #1. This is because BW #0 and BW#1 are orthogonal to each other between W₀ and W₁ and between W₂ and W₃,and, consequently, if the channel condition is regarded as substantiallythe same between the first LB and the second LB (S₀ and S₁) and betweenthe sixth LB and the seventh LB (S₂ and S₃), interference is not likelyto occur between the response signal of BW #0 and the response signal ofBW #1, while, if the channel condition is regarded as substantially thesame over the first LB to the seventh LB (S₀ to S₃), interference occursbetween the response signal of BW #1 and the response signal of BW #2.Therefore, in FIG. 8A, although interference occurs from PUCCH #15 toPUCCH #9, interference does not occur from PUCCH #6 to PUCCH #1.Interference in the vertical directions shown in FIG. 8A cannot berandomized only by the hopping patterns shown in FIGS. 7A and 7B.

Therefore, in the present example, the hopping patterns shown in FIGS.8A and 8B are used as second layer hopping patterns. In FIG. 8B, thearrangement order of PUCCH's on the cyclic shift axis is opposite tothat in FIG. 8A, and different offsets on the cyclic shift axis aregiven to PUCCH's associated with respective block-wise spreading codesequences.

Hopping in the present example is represented by equation 7. That is,the cyclic shift value CS_(index)(k,i,cell_(id)) in the present exampleis given by equation 7. Here, w represents a block-wise spreading codesequence index, and Hop_(offset)(w,j) represents the offset value thatvaries per slot and per block-wise spreading code sequence on the cyclicshift axis.

CS_(index)(k,i,w,cell_(id))=mod(init(k)+Hop_(LB)(i,cell_(id))+Hop_(slot)(k,j)+Hop_(offset)(w,j)12)  (Equation7)

Thus, according to the present example, it is possible to randomize notonly interference that occurs in the cyclic shift axis direction butalso interference that occurs in the block-wise spreading code sequenceaxis direction.

Example 1-3 FIG. 8C

Even by using the hopping pattern shown in FIG. 8C instead of thehopping pattern shown in FIG. 8B, it is possible to provide the sameeffect as in example 1-2. In FIG. 8C, the arrangement order of PUCCH'son the cyclic shift axis is opposite to that in FIG. 8A, and the PUCCH'sassociated with BW #1 (a second row) in FIG. 8A are associated with BW#2 (a third row), and the PUCCH's associated with BW #2 (a third row) inFIG. 8A are associated with BW #1 (a second row). That is, FIG. 8Creplaces BW #1 (a second row) and BW #2 (a third row) in FIG. 8A witheach other.

Example 1-4 FIGS. 9A and 9B

Even by using the hopping patterns shown in FIGS. 9A and 9B instead ofthe hopping patterns shown in FIGS. 8A and 8B, it is possible to providethe same effect as in Example 1-2. In FIG. 9B, the arrangement order ofPUCCH's on the cyclic shift axis is opposite to that in FIG. 9A, and thePUCCH's associated with BW #1 (a second row) in FIG. 9A are associatedwith BW #2 (a third row), and the PUCCH's associated with BW #2 (a thirdrow) in FIG. 9A are associated with BW #1 (a second row). That is, FIG.9B replaces BW #1 (a second row) and BW #2 (a third row) in FIG. 9A witheach other.

In example 1-2, PUCCH's using substantially the same cyclic shift valuesin slot 0 (e.g., PUCCH #0, PUCCH #6 and PUCCH #12 in FIG. 8A) usecompletely different cyclic shift values in slot 1 (FIG. 8B).

By contrast with this, in the present example, as shown in FIGS. 9A and9B, PUCCH's using substantially the same cyclic shift values in slot 0(e.g., PUCCH #0, PUCCH #1 and PUCCH #2 in FIG. 9A) also usesubstantially the same cyclic shift values in slot 1 (FIG. 9B). That is,PUCCH #0, PUCCH #1 and PUCCH #2 use two adjacent cyclic shift values ofcyclic shift values “0” and “1” in slot 0 (FIG. 9A), and also use twoadjacent cyclic shift values of cyclic shift values “10” and “11” inslot 1 (FIG. 9B). Therefore, when PUCCH #0, PUCCH #1 and PUCCH #2 areunused, unused resources (i.e., available resources) are subject toblock-based hopping in both slot 0 and slot 1. Therefore, according tothe present example, it is easily possible to allocate unused resourcesfor other purposes such as CQI (Channel Quality Indicator) transmission.

Embodiment 2

With the present embodiment, as shown in FIGS. 10A and 10B, amobile-station-specific hopping pattern in Embodiment 1 is the same inthe multiplication unit of an orthogonal sequence and varies between themultiplication units of orthogonal sequence.

To be more specific, as shown in FIGS. 10A and 10B, amobile-station-specific hopping pattern is the same in themultiplication unit of [W₀, W₁, W₂, W₃] in FIG. 1, that is, the hoppingpattern is the same between the unit of LB 0, LB 1, LB 5 and LB 6 inslot 0 and the unit of LB 7, LB 8, LB 12 and LB 13 in slot 1. Also, amobile-station-specific hopping pattern is the same in themultiplication unit of [F₀, F₁, F₂] in FIG. 1, that is, the hoppingpattern is the same between the unit of LB 2, LB 3 and LB 4 in slot 0and the unit of LB 9, LB 10 and LB 11 in slot 1. Further, amobile-station-specific hopping pattern varies between themultiplication unit of [W_(o), W₁, W₂, W₃] and the multiplication unitof [F₀, F₁, F₂]. Therefore, as shown in FIGS. 10A and 10B, a secondlayer hopping pattern is represented by four cyclic shift values on aper slot basis, and does not vary but is the same in the multiplicationunit of [W₀, W₁, W₂, W₃] or in the multiplication unit of [F₀, F₁, F₂].

Hopping of the present example is represented by equation 8. That is,the cyclic shift value CS_(index)(k,i,cell_(id)) used by the k-th PUCCHin the i-th LB (SC-FDMA symbol) in the cell of the cell index cell_(id),is given by equation 8.

CS_(index)(k,i,cell_(id))=mod(init(k)+Hop_(LB)(i,cell_(id))+Hop_(block)(k,l),12)  (Equation8)

Here, in equation 8, Hop_(block)(k,l) represents a second layer hoppingpattern that is common between a plurality of cells, “1” represents theindex of a second layer hopping pattern, and “i” and “1” hold therelationship shown in equation 9.

l=0 (i=0,1,5,6), l=1 (i=2,3,4), l=2 (i=7,8,12,13), l=3(i=9,10,11)  (Equation 9)

Here, FIGS. 11A and 11B show second layer hopping patterns in the unitsof LB 2, LB 3 and LB 4 in slot 0 and the units of LB 9, LB 10 and LB 11in slot 1. Also, the second layer hopping patterns in the units of LB 0,LB 1, LB 5 and LB 6 in slot 0 and the units of LB 7, LB 8, LB 12 and LB13 in slot 1 are the same as in Embodiment 1 (see FIGS. 7A and 7B).Here, referring to FIG. 7A and FIG. 11A, it is understood that PUCCH'sfront and rear adjacent to all PUCCH's of PUCCH #0 to PUCCH #17 on thecyclic shift axis are different between FIG. 7A and FIG. 11A. Forexample, while PUCCH #0 is front adjacent to PUCCH #1 and PUCCH #2 isrear adjacent to PUCCH #1 in FIG. 7A, PUCCH #4 is front adjacent toPUCCH #1 and PUCCH #5 is rear adjacent to PUCCH #1 in FIG. 11A.Therefore, it is possible to further randomize intra-cell interference.

Thus, according to the present embodiment, second layer hopping patternsinclude four cyclic shift values, so that it is possible to increase thenumber of second layer hopping patterns and further randomize intra-cellinterference.

Embodiments of the present invention have been described above.

Also, a PUCCH used for explanation in the above embodiments is thechannel for feeding back an ACK or NACK, and, consequently, may bereferred to as an “ACK/NACK channel.”

Also, it is equally possible to implement the present invention even inthe case of feeding back control information other than responsesignals.

Also, a mobile station may be referred to as a “terminal station,” “UE,”“MT,” “MS” or “STA (STAtion)”. Also, a base station may be referred toas “Node B,” “BS” or “AP.” Also, a subcarrier may be referred to as a“tone.” Also, a CP may be referred to as a “GI (Guard Interval)”.

Also, the error detecting method is not limited to CRC check.

Also, a method of performing conversion between the frequency domain andthe time domain is not limited to IFFT and FFT.

Also, cases have been described above with embodiments where the presentinvention is applied to mobile stations. However, the present inventionis also applicable to a fixed radio communication terminal apparatus ina stationary state and a radio communication relay station apparatusthat performs the same operations with a base station as a mobilestation. That is, the present invention is applicable to all radiocommunication apparatuses.

Although a case has been described with the above embodiments as anexample where the present invention is implemented with hardware, thepresent invention can be implemented with software.

Furthermore, each function block employed in the description of each ofthe aforementioned embodiments may typically be implemented as an LSIconstituted by an integrated circuit. These may be individual chips orpartially or totally contained on a single chip. “LSI” is adopted herebut this may also be referred to as “IC,” “system LSI,” “super LSI,” or“ultra LSI” depending on differing extents of integration.

Further, the method of circuit integration is not limited to LSI's, andimplementation using dedicated circuitry or general purpose processorsis also possible. After LSI manufacture, utilization of an FPGA (FieldProgrammable Gate Array) or a reconfigurable processor where connectionsand settings of circuit cells in an LSI can be reconfigured is alsopossible.

Further, if integrated circuit technology comes out to replace LSI's asa result of the advancement of semiconductor technology or a derivativeother technology, it is naturally also possible to carry out functionblock integration using this technology. Application of biotechnology isalso possible.

The disclosure of Japanese Patent Application No. 2007-257764, filed onOct. 1, 2007, including the specification, drawings and abstract, isincorporated herein by reference in its entirety.

INDUSTRIAL APPLICABILITY

The present invention is applicable to, for example, mobilecommunication systems.

1. A communication apparatus, comprising: a spreader configured to: whenan acknowledgement/negative acknowledgement (ACK/NACK) signal is to betransmitted, spread the ACK/NACK signal using an orthogonal sequencehaving a sequence index corresponding to a physical uplink controlchannel (PUCCH) number allocated to the apparatus and a sequence definedby a cyclic shift amount having an ACK/NACK cyclic shift indexcorresponding to the PUCCH number, the ACK/NACK cyclic shift index beingone of a set of cyclically continuous ACK/NACK cyclic shift indexes of aplurality of cyclically continuous cyclic shift indexes; and when achannel quality indicator (CQI) signal is to be transmitted, spread theCQI signal using a sequence defined by a cyclic shift amount having aCQI cyclic shift index corresponding to the PUCCH number, the CQI cyclicshift index being one of a set of cyclically continuous CQI cyclic shiftindexes of the plurality of cyclically continuous cyclic shift indexes,wherein the set of CQI cyclic shift indexes and the set of ACK/NACKcyclic shift indexes are mutually exclusive; and a transmitterconfigured to transmit spread signals.
 2. The communication apparatus ofclaim 1 wherein a difference in a cyclic shift amount between slotsdiffers among PUCCH numbers.
 3. The communication apparatus of claim 1,comprising: a changing section configured to change a cyclic shiftamount having the ACK/NACK cyclic shift index corresponding to the PUCCHnumber between symbols, so that a difference in the cyclic shift amountbetween the symbols is common in a cell, and to change the cyclic shiftamount having the ACK/NACK cyclic shift index corresponding to the PUCCHnumber between slots, so that a difference in the cyclic shift amountbetween the slots differs amongst PUCCH numbers and the ACK/NACK cyclicshift index corresponding to the PUCCH number in each of the slots isone of the set of ACK/NACK cyclic shift indexes.
 4. The communicationapparatus of claim 1 wherein the plurality of cyclic shift indexesconsists of twelve integers.
 5. The communication apparatus of claim 4wherein the set of ACK/NACK cyclic shift indexes comprises less than 12integers.
 6. The communication apparatus of claim 1 wherein thecommunication apparatus is a mobile station.
 7. A communicationapparatus, comprising: a determining section configured to: determinecyclic shift indexes for acknowledgement/negative acknowledgement(ACK/NACK) signals based on slot indexes and physical uplink controlchannel (PUCCH) numbers assigned to the communication apparatus suchthat a determined ACK/NACK cyclic shift index is one of a set ofcyclically continuous ACK/NACK cyclic shift indexes of a plurality ofcyclically continuous cyclic shift indexes; and determine cyclic shiftindexes for channel quality indicator (CQI) signals such that adetermined CQI cyclic shift index is one of a set of cyclicallycontinuous CQI cyclic shift indexes of the plurality of cyclicallycontinuous cyclic shift indexes, wherein the set of ACK/NACK cyclicshift indexes and the set of CQI cyclic shift indexes are mutuallyexclusive; a spreader configured to spread signals based in part ondetermined cyclic shift indexes; and a transmitter configured totransmit spread signals.
 8. The communication apparatus of claim 7wherein the determining section is configured to determine cyclic shiftindexes for ACK/NACK signals based on symbol indexes and a value commonin a cell.
 9. The communication apparatus of claim 8 wherein thedetermining section is configured to determine cyclic shift indexes forACK/NACK signals based on a sum of a first term value and a second termvalue, the first term value being based on a symbol index and the valuecommon in the cell and the second term value being based on a slot indexand a PUCCH number.
 10. The communication apparatus of claim 7, whereinthe plurality of cyclic shift indexes consists of twelve integers. 11.The communication apparatus of claim 7 wherein the spreader isconfigured to spread a signal based on a cyclic shift amount having adetermined cyclic shift index.
 12. The communication apparatus of claim11 wherein a difference in a cyclic shift amount between slots differsamong PUCCH numbers.
 13. The communication apparatus of claim 11,comprising: a changing section configured to change a cyclic shiftamount having an ACK/NACK cyclic shift index corresponding to a PUCCHnumber between symbols, so that a difference in the cyclic shift amountbetween the symbols is common in a cell, and to change the cyclic shiftamount having the ACK/NACK cyclic shift index corresponding to the PUCCHnumber between slots, so that a difference in the cyclic shift amountbetween the slots differs amongst PUCCH numbers and the ACK/NACK cyclicshift index corresponding to the PUCCH number in each of the slots isone of the set of ACK/NACK cyclic shift indexes.
 14. The communicationapparatus of claim 7 wherein the communication apparatus is a mobilestation.
 15. A method, comprising: when an ACK/NACK signal is to betransmitted, spreading the ACK/NACK signal using an orthogonal sequencehaving a sequence index corresponding to an allocated physical uplinkcontrol channel (PUCCH) number and a sequence defined by a cyclic shiftamount having an ACK/NACK cyclic shift index corresponding to the PUCCHnumber, the ACK/NACK cyclic shift index being one of a set of cyclicallycontinuous ACK/NACK cyclic shift indexes of a plurality of cyclicallycontinuous cyclic shift indexes; and transmitting the spread ACK/NACKsignal; and when a CQI signal is to be transmitted, spreading the CQIsignal using a sequence defined by a cyclic shift amount having a CQIcyclic shift index corresponding to the PUCCH number, the CQI cyclicshift index being one of a set of cyclically continuous CQI cyclic shiftindexes of the plurality of cyclically continuous cyclic shift indexes,wherein the set of CQI cyclic shift indexes and the set of ACK/NACKcyclic shift indexes are mutually exclusive; and transmitting the spreadCQI signal.
 16. The method of claim 15 wherein a difference in a cyclicshift amount between slots differs among PUCCH numbers.
 17. The methodof claim 15, comprising: changing a cyclic shift amount having theACK/NACK cyclic shift index corresponding to the PUCCH number betweensymbols, so that a difference in the cyclic shift amount between thesymbols is common in a cell, and changing the cyclic shift amount havingthe ACK/NACK cyclic shift index corresponding to the PUCCH numberbetween slots, so that a difference in the cyclic shift amount betweenthe slots differs amongst PUCCH numbers and the ACK/NACK cyclic shiftindex corresponding to the PUCCH number in each of the slots is one ofthe set of ACK/NACK cyclic shift indexes.
 18. A method, comprising:determining cyclic shift indexes for acknowledgement/negativeacknowledgement (ACK/NACK) signals based on slot indexes and physicaluplink control channel (PUCCH) numbers assigned to the communicationapparatus such that a determined ACK/NACK cyclic shift index is one of aset of cyclically continuous ACK/NACK cyclic shift indexes of aplurality of cyclically continuous cyclic shift indexes; determiningcyclic shift indexes for channel quality indicator (CQI) signals suchthat a determined CQI cyclic shift index is one of a set of cyclicallycontinuous CQI cyclic shift indexes of the plurality of cyclicallycontinuous cyclic shift indexes, wherein the set of ACK/NACK cyclicshift indexes and the set of CQI cyclic shift indexes are mutuallyexclusive; spreading signals based in part on determined cyclic shiftindexes; and transmitting spread signals.
 19. The method of claim 18,comprising determining cyclic shift indexes for ACK/NACK signals basedon symbol indexes and a value common in a cell.
 20. The method of claim19, comprising determining cyclic shift indexes for ACK/NACK signalsbased on a sum of a first term value and a second term value, the firstterm value being based on a symbol index and the value common in thecell and the second term value being based on a slot index and a PUCCHnumber.
 21. The method of claim 18, comprising spreading a signal basedon a cyclic shift amount having a determined cyclic shift index.
 22. Themethod of claim 21, comprising: changing a cyclic shift amount having anACK/NACK cyclic shift index corresponding to a PUCCH number betweensymbols, so that a difference in the cyclic shift amount between thesymbols is common in a cell; and changing the cyclic shift amount havingthe ACK/NACK cyclic shift index corresponding to the PUCCH numberbetween slots, so that a difference in the cyclic shift amount betweenthe slots differs amongst PUCCH numbers and the ACK/NACK cyclic shiftindex corresponding to the PUCCH number in each of the slots is one ofthe set of ACK/NACK cyclic shift indexes.